High-quality rapid laser drilling of transparent hard materials

The high-quality, high-efficiency micro-hole drilling of structural ceramics to improve the thermal conductivity of hot-end parts or achieve high-density electronic packaging is still a technical challenge for conventional processing techniques. Recently, the laser drilling method (LDM) has become the preferred processing tool for structural ceramics, and it plays an irreplaceable role in the industrialized processing of group holes on structural ceramic surfaces. A variety of LDMs such as long pulsed laser drilling, short pulsed laser drilling, ultrafast pulsed laser drilling, liquid-assisted laser drilling, combined pulse laser drilling have been developed to achieved high-quality and high-efficiency micro-hole drilling through controlling the laser–matter interaction. This article reviews the characteristics of different LDMs and systematically compares the morphology, diameter, circularity, taper angle, cross-section, heat affect zone, recast layer, cracks, roughness, micro–nano structure, photothermal effect and photochemical reaction of the drilling. Additionally, exactly what processing parameters and ambient environments are optimal for precise and efficient laser drilling and their recent advancements were analyzed. Finally, a summary and outlook of the LDM technology are also highlighted.

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Some problems of objective-prism spectra classification

Symposium - International Astronomical Union ◽

10.1017/s0074180900053183 ◽

1966 ◽

Vol 24 ◽

pp. 51-52

Author(s):

E. K. Kharadze ◽

R. A. Bartaya

Keyword(s):

Short Wave ◽

High Quality ◽

Stellar Spectra ◽

Objective Prism

The unique 70-cm meniscus-type telescope of the Abastumani Astrophysical Observatory supplied with two objective prisms and the seeing conditions characteristic at Mount Kanobili (Abastumani) permit us to obtain stellar spectra of a high quality. No additional design to improve the “climate” immediately around the telescope itself is being applied. The dispersions and photographic magnitude limits are 160 and 660Å/mm, and 12–13, respectively. The short-wave end of spectra reaches 3500–3400Å.

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A non-cyanide method of electropolishing silver

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100107873 ◽

1978 ◽

Vol 36 (1) ◽

pp. 146-147

Author(s):

R. L. Lyles ◽

S. J. Rothman ◽

W. Jäger

Keyword(s):

Electron Microscopy ◽

Sulphuric Acid ◽

Methyl Alcohol ◽

Health Hazards ◽

Silver Alloy ◽

High Quality ◽

Silver Alloys ◽

Free Sample ◽

Specimen Quality ◽

Standard Techniques

Standard techniques of electropolishing silver and silver alloys for electron microscopy in most instances have relied on various CN recipes. These methods have been characteristically unsatisfactory due to difficulties in obtaining large electron transparent areas, reproducible results, adequate solution lifetimes, and contamination free sample surfaces. In addition, there are the inherent health hazards associated with the use of CN solutions. Various attempts to develop noncyanic methods of electropolishing specimens for electron microscopy have not been successful in that the specimen quality problems encountered with the CN solutions have also existed in the previously proposed non-cyanic methods.The technique we describe allows us to jet polish high quality silver and silver alloy microscope specimens with consistant reproducibility and without the use of CN salts.The solution is similar to that suggested by Myschoyaev et al. It consists, in order of mixing, 115ml glacial actic acid (CH3CO2H, specific wt 1.04 g/ml), 43ml sulphuric acid (H2SO4, specific wt. g/ml), 350 ml anhydrous methyl alcohol, and 77 g thiourea (NH2CSNH2).

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A High Resolution Scanning Microscope

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100101529 ◽

1968 ◽

Vol 26 ◽

pp. 356-357

Author(s):

A. V. Crewe ◽

J. Wall ◽

L. M. Welter

Keyword(s):

High Resolution ◽

Field Emission ◽

Spherical Aberration ◽

Focal Length ◽

Spot Size ◽

Emission Source ◽

Field Of View ◽

Scanning Microscope ◽

Magnetic Lens ◽

High Quality

A scanning microscope using a field emission source has been described elsewhere. This microscope has now been improved by replacing the single magnetic lens with a high quality lens of the type described by Ruska. This lens has a focal length of 1 mm and a spherical aberration coefficient of 0.5 mm. The final spot size, and therefore the microscope resolution, is limited by the aberration of this lens to about 6 Å.The lens has been constructed very carefully, maintaining a tolerance of + 1 μ on all critical surfaces. The gun is prealigned on the lens to form a compact unit. The only mechanical adjustments are those which control the specimen and the tip positions. The microscope can be used in two modes. With the lens off and the gun focused on the specimen, the resolution is 250 Å over an undistorted field of view of 2 mm. With the lens on,the resolution is 20 Å or better over a field of view of 40 microns. The magnification can be accurately varied by attenuating the raster current.

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Measurements in 3D images

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100086349 ◽

1991 ◽

Vol 49 ◽

pp. 408-409

Author(s):

John C. Russ

Keyword(s):

Three Dimensional ◽

Image Plane ◽

X Rays ◽

Traditional Use ◽

3D Images ◽

Confocal Scanning Laser Microscope ◽

Hard Materials ◽

Depth Direction ◽

Confocal Scanning ◽

Confocal Scanning Laser

Three-dimensional (3D) images consisting of arrays of voxels can now be routinely obtained from several different types of microscopes. These include both the transmission and emission modes of the confocal scanning laser microscope (but not its most common reflection mode), the secondary ion mass spectrometer, and computed tomography using electrons, X-rays or other signals. Compared to the traditional use of serial sectioning (which includes sequential polishing of hard materials), these newer techniques eliminate difficulties of alignment of slices, and maintain uniform resolution in the depth direction. However, the resolution in the z-direction may be different from that within each image plane, which makes the voxels non-cubic and creates some difficulties for subsequent analysis.

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Quantitative defect studies in semiconductor TEM samples prepared by low angle ion milling

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100138932 ◽

1995 ◽

Vol 53 ◽

pp. 512-513

Author(s):

L. Mulestagno ◽

J.C. Holzer ◽

P. Fraundorf

Keyword(s):

Sample Preparation ◽

Milling Time ◽

High Density ◽

Low Density ◽

Ion Milling ◽

High Quality ◽

Variable Angle ◽

Major Disadvantage ◽

Induced Defects

Due to the wealth of information, both analytical and structural that can be obtained from it TEM always has been a favorite tool for the analysis of process-induced defects in semiconductor wafers. The only major disadvantage has always been, that the volume under study in the TEM is relatively small, making it difficult to locate low density defects, and sample preparation is a somewhat lengthy procedure. This problem has been somewhat alleviated by the availability of efficient low angle milling.Using a PIPS® variable angle ion -mill, manufactured by Gatan, we have been consistently obtaining planar specimens with a high quality thin area in excess of 5 × 104 μm2 in about half an hour (milling time), which has made it possible to locate defects at lower densities, or, for defects of relatively high density, obtain information which is statistically more significant (table 1).

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Structural changes in silicon-on-insulator material during post-implantation annealing

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100145054 ◽

1986 ◽

Vol 44 ◽

pp. 736-737

Author(s):

C. O. Jung ◽

S. J. Krause ◽

S.R. Wilson

Keyword(s):

Integrated Circuits ◽

Oxide Layer ◽

High Speed ◽

Structural Changes ◽

Device Fabrication ◽

Silicon On Insulator ◽

High Quality ◽

Radiation Hardened ◽

Post Implantation ◽

Very High

Silicon-on-insulator (SOI) structures have excellent potential for future use in radiation hardened and high speed integrated circuits. For device fabrication in SOI material a high quality superficial Si layer above a buried oxide layer is required. Recently, Celler et al. reported that post-implantation annealing of oxygen implanted SOI at very high temperatures would eliminate virtually all defects and precipiates in the superficial Si layer. In this work we are reporting on the effect of three different post implantation annealing cycles on the structure of oxygen implanted SOI samples which were implanted under the same conditions.

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